Semiconductors devices such as memory devices and processors reside in many computers and electronic products to store and process data.
A typical memory device or processor includes logic circuits to perform logic functions. Some logic circuits give the results of the logic functions in form of resulting signals with a relatively low voltage or low signal swing. In some cases, the resulting signals may have signal levels at inappropriate levels to be considered as full logic levels (logic one and logic zero) useful for further processing. In these cases, level restore circuits are used to restore the resulting signals to the full logic levels. Some level restore circuits have a sense amplifier with sense amplifier input nodes to sense the resulting signals provided by the logic circuits to generate output signals with the full logic levels.
A typical sense amplifier includes transistors. Transistors are susceptible to mismatches due to variations in manufacturing process. Mismatches in the transistors may create an offset voltage between the input nodes of the sense amplifier when the sense amplifier is reset.
The offset voltage may result in invalid logic levels at the output nodes of the typical sense amplifier after the reset. Further, mismatches in the transistors often require the signal swing of the resulting signals at or the input signals at the input nodes of the sense amplifier to be above a specific signal swing. Thus, in cases where the signal swing of the input signals is relatively low, a typical sense amplifier may be unreliable to produce output signals with correct logic levels.